Impact of indoor ventilation on TB transmission risk: implications of climate change

BACKGROUND Due to rising temperatures, individuals are predicted to spend more time in under-ventilated indoor spaces, increasing TB transmission risk. We studied the impact of indoor ventilation on TB transmission risk in homes of persons with TB and in health care facilities in Puducherry, India. METHODS We measured ventilation in air changes per hour (ACH) under different ventilation conditions using a carbon dioxide decay method. We estimated transmission risk using the Wells-Riley equation. RESULTS Forty-five measurements were taken in 13 homes and 7 health care spaces. In the closed condition (doors and windows closed, fans off), ACH was low (mean 2.23, standard deviation [SD] 2.27) and TB transmission risk was high at 62% (SD 31%). When air conditioning (AC) was on, ACH reduced to 0.75 (SD 0.51), and TB transmission was highest at 76% (SD 13%). Natural ventilation significantly improved ACH (mean 9.46, SD 3.90; P P CONCLUSION TB transmission risk in homes and health care spaces is high, especially with AC on. Adapting to rising temperatures using novel methods of ventilation, cooling, and air purification is critical to TB infection control in the era of climate change. .